Sterile insect technique promising in fight against greenhouse pepper pest

By Jane Robinson

Ontario’s greenhouse pepper growers are struggling to control a very problematic invasive insect, but have very few effective options. Pepper weevils are threatening the province’s $420 million greenhouse pepper industry – a high value crop that covers about 520 hectares (1,285 acres) in Ontario.

University of Guelph researcher Dr. Cynthia Scott-Dupree is testing a genetic control strategy that could bring much-needed hope to growers.

“Pepper weevils began causing substantial economic losses in Ontario in 2015,” says Scott-Dupree, a professor in the School of Environmental Sciences and Bayer Chair in Sustainable Pest Management.  “There really aren’t any effective insecticides that control the adult, and the direct damage caused to the pepper is invisible until you cut it open.”

Adult female pepper weevils lay a single egg in a puncture wound on the surface of the pepper. When the egg hatches, the larvae chew into the pepper to feed. The adult emerges inside the fruit, feeds on the pepper a little longer, mates and then exits the fruit. And the cycle starts all over.

Scott-Dupree started working on sterile insect technique (SIT) about five years ago to control a leafminer in Ontario-grown chrysanthemums. She was then approached by Bruce Power about the potential to use gamma radiation to mitigate insect pest problems in Ontario agriculture.